it's actually not that hard to animate a car in constant motion. You need to first develop the actual spin so that it can move (only if there is a bone to pick there), or you can do it eitehr to ways; use GMOD with the same map and everything for just that scene or two, or you can just give the car motion with moving the wheels.

When I first got here and was trying how to even move a character from point A to point B and tell SFM to have the model slowly move between the two points this was the video that gave me the idea on how to do it: http://www.youtube.com/watch?v=zEe4N_QhFAE

I'm sorry it's not exactly what you are looking for, this is just the best I found when I was in your position, it helped me get a pretty good basic understanding. Make sure to go through the Valve tutorials on youtube also, just so you know how to get around the program and such. Hope this helps get you in the right direction.